The Histopathology Comparative Study Of Rabbit Model Between Osteonecrosis And Osteoporosis

Objective:To establish the models of Osteonecrosis and osteoporosis of bone with white rabbit, to explore the correlate relationship and mechanism according to comparison the changes between them. M ethods:32 3-months old female New Zealand white rabbits were divided randomly into 4 groups:Group A (intramuscular hormone, n=8); Group B (spaying, n=8); Group C (spaying+intramuscular hormone, n=8); Group D (normal control group, sham operation+intramuscular normal saline, n=8). The models were spayed via the hypogastrium median incision in Group B,C, the steps were same of the models in Group A,D except for spaying. The models were underwent abdominal irrigation with metronidazole during operation and were intramuscular with 100 thousand unit penicillin per kilogram once a week for infection prevention. The models were intramuscular with hydrocortisone 7.5 milligram per kilogram twice a week in Group A,C at 1 week postoperatively. Models in Group B, D were intramuscular with identical capacity normal saline. The bone mineral density of the models were determined after drug administration at 5 and 10 weeks respectively, then the bilateral femoral head of 4 models were taken with HE dyeing,oil red O dyeing and detected with scanning electron microscope. Results: The BMD of lumbar and femoral near-end of models at the 5th and 10th weeks postoperatively were significantly decreased in Group A, B and C than preoperation and the same period in Group D(P<0.05). The mean values of BMD in 10 weeks postoperatively in Group D were significantly decreased than preoperation and the mean values minus 2.0SD of the same period in Group D(P<0.05). The positive rate of empty bone lacunas were significantly increased in Group A, B, C than Group D(P<0.05), and the trabeculae showed different degree of porotic, some fractured in Group A, B, C at the 5th week after modeling. The positive rate of empty bone lacunas were significantly increased in Group A, B, C than Group D(P<0.05), and The different degree hyperplasia of fat cells existed in femoral head marrow cavity, the trabeculae showed porotic, manifesting thinning, disorganization, fragmentation at the 10th week. Yet the trabeculae were compact, eumorphism and homogeneous distribution in bone lacunas, the fat cell were normomorph and moderate in bone marrow in Group D. Conclusion:The white rabbit model of avascular necrosis of the Femoral Head and osteoporosis are established successfully by spaying and intramuscular hormone. There are similar pathology changes in the early period between two diseases, but they are different. Osteoporosis is mainly due to the influence of the activity of osteoblast and osteoclast,and the balance between them.The hyperplasia of adipocyte and the fatty degeneration of osteocyte play a leafing role in the course of osteonecrosis.It is of far reaching important in theory and practice to investigate the pathogenesis and regulation of osteonecrosis and osteoporosis.